Wheel chair with monocoque-type body

ABSTRACT

The invention relates to a small vehicle, particularly a wheel chair, comprising a chassis having a monocoque-type main body to which arms for supporting wheels are coupled and at which a seat component can be attached. The main body is designed as a monolith and preferably is manufactured from an extruded profile of aluminium or an aluminium alloy, or is made of wound sheet metal or of plastic. Four arms for two freely pivotable supporting wheels and two driving wheels are springably coupled to said main body.

BACKGROUND OF THE INVENTION

[0001] The invention relates to a small vehicle, particularly a wheelchair comprising a chassis having a monocoque-type main body.

[0002] Wheel chairs, including those which are driven by a motor,usually comprise a wheel chair frame in which a seat is integrated, twowheels which can be driven and two wheels which can be either freelypivoted or steered by a motor wherein said wheels are directly coupledto said frame. The drivable wheels can be driven manually via hand rimsor driven by a motor. Such wheel chairs often comprise a foldingmechanism which allows folding of the wheel chair frame in order toreduce the overall size for the purpose of transport of the wheel chair.A wheel chair of this kind is for instance disclosed in EP 0 790 049 A2.

[0003] Wheel chairs of the kind as explained above are rather unsuitablefor outdoor operation, that is for operation outside houses andparticularly on uneven tracks, for instance tracks in fields or woods.The frame construction as described above has only a relatively lowstability. Moreover, direct coupling of the wheels to a pipe frame onlyallows a suspension which is insufficient for uneven tracks since theonly spring system is usually the one provided by the pneumatic tires.

[0004] Wheel chairs having acceptable driving and performancecharacteristics for outdoor operation are also known. However, theamount of time, work and effort needed for dismantling such wheel chairsfor the purpose of transport is not acceptable.

[0005] There is a need for a small vehicle, particularly a wheel chairwhich has sufficient stability suitable also for outdoor operation aswell as a drivability suitable for outdoor operation and, at the sametime, can be dismantled so that transport thereof is possible in atypical trunk of an automobile.

SUMMARY OF THE INVENTION

[0006] The small vehicle according to the present invention has achassis having a monocoque-type main body. Four arms for supporting thewheels are springably coupled to the main body and a seat component ismounted at said main body. While according to the prior art discussedabove a seat is integrated in a pipe frame and the wheels are directlycoupled to said pipe frame, in case of the small vehicle according tothe present invention the monocoque-type main body performs the functionof supporting the suspension. The main body has sufficient stability toperform this supporting function.

[0007] The main body is designed as a monolith. This means that the mainbody has a block-like structure which provides sufficient stability, isrelatively light weight and has corresponding attachment points forsupporting the arms and for receiving the seat component. For this, themain body for example can be manufactured from an extruded profile, i.e.it can be provided in the form of a hard alloy extrusion or extrudedshape made of aluminium or an aluminium alloy. Moreover, the main bodycan be made of a suitable plastic, a compound material, or of woundsheet metal.

[0008] Two freely pivotable wheels and two driving wheels can bedetachably mounted at said at said arms, preferably by means of quickrelease devices. The driving wheels preferably comprise a hub motor,that is a motor which is provided in the region of the wheel hub.Accordingly, there is no necessity of providing a drive train from thevehicle frame to the driving wheels. The torque for driving the vehicleis provided in the hub motor and the stationary portion of the hub motormerely must be supported at the corresponding arm via a suitable supportelement to enable driving operation.

[0009] Electric motors are particularly suited for driving such smallvehicles. Storage batteries necessary for power supply can be mounted atthe main body, preferably via suitable quick release devices which allowquick and easy change of the storage batteries. Connection points forthe storage batteries can be provided at opposite sides of the mainbody. Moreover, there can be provided several connecting points forselective operation with one or several storage batteries, wherein, incase the vehicle is to be operated with only one storage battery, thisstorage battery is mounted in a central position with respect to thecenter axis of the vehicle, while, if the vehicle is to be operated withseveral storage batteries, these storage batteries are mountedsymmetrically with respect to the center axis of the vehicle.

[0010] The seat component of the small vehicle according to the presentinvention preferably comprises a seat, a back of seat and foot rests aswell as two arm rests and is provided as a complete unit. This unit isadapted to be mounted to the main body and to be dismounted therefrom bymeans of a quick release device. The seat component can be foldable. Dueto the modular structure of the small vehicle the seat can be designedwith particular view to ergonomics so that also seat pans for seriouslyhandicapped persons can be used. Moreover, the seat component can berotatably arranged so that upon turning the seat by 180° a vehiclehaving rear wheel drive will become a vehicle which has front wheeldrive.

[0011] The arms for supporting the freely pivotable wheels arepreferably designed as springably supported dual arms. This ensures thatthe caster of the freely pivotable wheels remains essentially constantover the entire range of spring, particularly in case the freelypivotable wheels are coupled to the arms by means of plug-in axles whichextend vertically to the ground. In case there is only a limited travelof the spring system, the front arms also can be designed as mono-arms.

[0012] The arms provided for supporting the driving wheels arepreferably designed as longitudinally arranged arms which are supportedat the main body via a spring/shock absorber unit.

[0013] A small vehicle designed as a wheel chair as explained above hasexcellent stability. The wheels may be springably supported to alsoallow operation on uneven tracks. At the same time, the structure anddesign of the wheel chair allow it to be dismantled into singlecomponents, making it possible to transport the wheel chair in the trunkof a common automobile. After the four wheels are detached from thearms, which for instance, can be done very easily if plug-in axles andquick release devices are used, and after the seat component and, as thecase may be, storage batteries are removed, only the main body and thefour arms, remain. This module unit has a flat shape which can be easilytransported. The wheels and the storage batteries also can be easilystowed away and the seat component can also be brought into aspace-saving flat form, if a folding mechanism is used.

[0014] Particularly in cases where electric motors are used as drivingunits, the main body can have interfaces for electric circuits at theconnection points of the driving wheels and/or the seat component and/orthe storage batteries. A control panel, including a console, can beprovided at an arm rest of the seat component. Furthermore, it ispossible to provide wireless signal transmission between the controlpanel and the driving wheels. If hub motors are provided, a separatecontrol unit may be provided for each hub motor. In that case, it willnot be necessary to provide wires for control signals. If the storagebatteries are attached to the main body, it will only be necessary toprovide power transmission to the hub motors.

[0015] If the storage batteries are also disposed adjacent the wheelhubs of the driving wheels and a wireless signal transmission forcontrol signals is provided, it will not be necessary to provide anywires between the frame and the wheels.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the following description, the invention is further explainedin connection with a preferred embodiment making reference to thedrawing in which

[0017]FIG. 1 is a perspective representation of a vehicle where theparts are taken apart in exploded view;

[0018]FIG. 2 is a perspective representation of the vehiclecorresponding to FIG. 1 wherein the main components except a controlpanel are depicted as being assembled;

[0019]FIG. 3 is a perspective depiction of the wheel chair according toFIGS. 1 and 2 where the seat component is omitted;

[0020]FIG. 4 is a depiction corresponding to FIG. 3 wherein anadditional protective cage is attached;

[0021]FIG. 5 is a side view of the representation according to FIG. 3;

[0022]FIG. 6 is a side view of a freely pivotable wheel having aclimbing device in a position before a step is contacted; and

[0023]FIG. 7 is a representation corresponding to FIG. 6 in which a stepis negotiated.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0024]FIG. 1 shows a wheel chair as an embodiment of the presentinvention in a so-called exploded view, i.e. with the parts taken apart.The main body 10 is provided in the form of a hard alloy extrusion orextruded shape made of an aluminium alloy 11. The hard alloy extrusion11 is closed at both longitudinal ends by corresponding end plates 12and respective bolts. Internal reinforcing members (not shown) or othercomponents, for instance switching units etc. (not shown) can beprovided in the essentially hollow inner space of the main body 10. Onthe upper side 13 of the main body 10 there is provided a receiving unit14 which serves for mounting of a seat component 50 by means of a quickrelease device which is not shown in detail.

[0025] The seat component 50 comprises frame profiles which togetherwith fabric or upholstery provide a seat 51, a seat back 52, a foot rest53 and a strut 54 for mounting control panel 60. It is understood thatarmrests (not shown) can be provided on both sides.

[0026] It is also clear that other structures are possible for the seatcomponent; for instance, a seat and a seat back and, as the case may be,corresponding side parts. The whole seat component 50 can be provided asa monocoque structure and can have corresponding connecting elements forconnecting the seat component to the main body or to a correspondingseat frame.

[0027] The seat component is provided with a folding mechanism whichallows the seat component 50 to fold when it is detached from the mainbody 10 so that the seat can be easily transported as one element ofsubstantially flat shape.

[0028] On the left side and on the right side, with reference to thedriving direction of the vehicle, two front arms 20 and two rear arms30, respectively, are connected to the main body 10. The rear arms 30are designed as longitudinal arms which are supported at the main body10 by means of a spring/shock absorber unit 31. The front arms 20 aredesigned as dual arms which are connected to each other by aspring/shock absorber mechanism which is disposed within the main body10 and which is not shown in the drawings.

[0029] The two driving wheels 35 are coupled to the rear arms 30 viahorizontally extending plug-in axles 36 and via quick release deviceswhich are not shown in detail. Two front wheels 25, which are freelypivotable, are coupled to the front arms 20 via vertically extendingplug-in axles 26 and via quick release devices which are also not shownin detail. As can be seen for instance from FIGS. 5 to 7, the positionof the axis of rotation 27 of the front wheel 25 is offset with respectto the position of the plug-in axle 26. Consequently, a caster isprovided so that the front wheels 25 are always oriented towards thedriving direction when the vehicle is driving straight ahead. Thesteering of the wheel chair is effected by separate control of bothdriven rear wheels 35. Preferably, the driving force is provided by hubmotors, i.e. electric motors which are provided in the hub region of thewheels (but are not shown in detail). Steering commands are input via acontrol panel 60.

[0030] The front arm 20 (illustrated as a dual arm) is designed in a waythat the caster of the front wheel 25 remains substantially constantover the entire range of travel of the spring system.

[0031] One or several storage batteries 70 can be hooked to the mainbody 10 via quick release devices. The quick release devices forsecuring the storage batteries 70 comprise interfaces for electriccircuits which provide electric connection of the storage batteries 70to the hub motors.

[0032] A protection device in the form of a protective cage 80 is,preferably detachably, attached to the main body 10.

[0033] A climbing device 28 is provided at each of the front wheels 25.There is a pair of climbing devices 28 for each front wheel 25 which issupported on both sides of each front wheel 25 and biased in a way sothat under normal operational conditions they are in a position which isdepicted in FIG. 6. The climbing device 28 can be pivoted over a certaindistance in the direction indicated by arrow A in FIGS. 6 and 7 in thedirection of rotation of the wheel with the pivotal axis indicated atreference number 29.

[0034] For the sake of simplicity, only one front wheel 25 is depictedin FIGS. 6 and 7 in order to explain the function of the climbing device28. When the wheel chair travels in the direction of a curb with thefront wheel leading, the climbing device 28 initially is in its upperpivotal position due to the bias force of the spring. When the climbingdevice 28 gets in contact with curb 90, the climbing device 28 ispivoted in the direction of rotation of the front wheel 25 due to thedriving force provided by the driving wheels. As a result, the frontwheel 25 is lifted until it gets in contact with the curb in anappropriate position so that upon further travel of the vehicle the curb90 can be negotiated.

[0035] Due to the fact that the climbing devices 28 are directly coupledto the freely rotatable front wheels 25, such climbing devices 28 arealways in a suitable orientation with respect to an obstacle,particularly in such cases where a curb or another step is approached atan angle. It is clear that the climbing device also can be directlycoupled to the main body.

[0036] The seat component 50, the storage batteries 70, the rear wheels35 and the front wheels 25 can be removed by means of simple quickrelease devices for dismantling the wheel chair. After being removed,the seat component 50 can be folded. Accordingly, single components areprovided which can be transported in a space-saving manner and which canbe accommodated in the trunk of a common automobile. The ability to beeasily dismantled further provides that the single components have arelatively low weight so chat the components can be easily stowed away.The provision of quick release devices facilitates dismantling of thewheel chair also for technically untalented persons and without anytools.

[0037] Even though the wheel chair of the present invention is easilydismantled, it is suitable for outdoor use. It combines the comfort offour spring-suspended wheels and the stability required for outdooroperation with the low weight and transportability of a common indoorwheel chair.

[0038] Although the invention has been described with reference toexemplary embodiments, it is not limited thereto. Rather, the appendedclaims should be construed to include other variants and embodiments ofthe invention which may be made by those skilled in the art withoutdeparting from the true spirit and scope of the present invention.

We claim:
 1. A wheel chair comprising: a chassis having a monocoque-type main body designed as a monolith, four arms for supporting wheels are springably coupled to the main body; and the main body receives a seat component.
 2. The wheel chair as claimed in claim 1, wherein the main body is made from an extruded profile.
 3. The wheel chair as claimed in claim 1, wherein the main body is made of aluminium or an aluminium alloy.
 4. The wheel chair as claimed in claim 1, wherein the main body is made of wound sheet metal.
 5. The wheel chair as claimed in claim 1, wherein the main body is made of plastic.
 6. The wheel chair according to claim 1, wherein two freely pivotable wheels and two driving wheels are provided.
 7. The wheel chair according to claim 6, wherein said freely pivotable wheels and said driving wheels are detachably mounted at said arms via quick release devices.
 8. The wheel chair according to claim 6, wherein said driving wheel has a hub motor.
 9. The wheel chair according to claim 6, wherein said driving wheel is driven by an electric motor.
 10. The wheel chair according to claim 1, wherein said seat component is detachably mounted at said main body via a quick release device.
 11. The wheel chair according to claim 1, wherein one or several storage batteries are mounted on said main body.
 12. The wheel chair according to claim 11, wherein said one or several storage batteries are mounted at one or both of two opposite sides of said main body.
 13. The wheel chair according to claim 11, wherein one or several storage batteries are mounted on said main body, wherein, in case of operation with only one storage battery, the one storage battery is mounted in a central position with respect to a center axis of the vehicle, whereas, in case of operation with several storage batteries, the several storage batteries are mounted symmetrically with respect to the center axis of the vehicle.
 14. The wheel chair according to claim 1, wherein said seat component comprises a seat, a seat back, at least one arm rest, and a foot rest, and the seat is detachably mounted on said main body as a complete unit via a quick release device.
 15. The wheel chair according to claim 14, wherein said seat component is foldable.
 16. The wheel chair according to claim 1, wherein said four arms comprise front arms for supporting pivotable wheels, and said front arms are designed as springably supported dual arms defining a caster of said pivotable wheels that remains substantially constant over the range of travel of a spring system defined by said springable coupling.
 17. The wheel chair according to claim 7, wherein said quick release device for detachably mounting said pivotable wheel at a front arm, said quick release device comprises a plug-in axle extending perpendicular to the ground
 18. The wheel chair according to claim 1, wherein said four arms comprise rear arms for supporting driving wheels, and said rear arms are designed as longitudinal arms which are supported at said main body via a spring/shock absorber unit.
 19. The wheel chair according to claim 1, wherein said main body defines interface for electric circuits at mounting locations defined by the group consisting of mounting locations for driving wheels, said seat component, and storage batteries.
 20. The wheel chair according to claim 1, wherein said seat component is mounted to said main body, said seat component being constructed as a body frame and having a monocoque construction, and the seat component being rotatable about 180°.
 21. A wheel chair comprising: a chassis having a monocoque-type main body designed for use as a single piece; four arms for supporting wheels, wherein the arms are springably coupled to the main body; and the main body comprises a quick release for a seat component.
 22. A wheel chair comprising: a chassis having a monocoque-type main body designed for use as a single piece; four arms for supporting wheels, in which the arms are springably coupled to the main body; and the main body supports a seat component. 